This chapter discusses using MySQL Cluster with MySQL Cluster Connector for Java, which
includes ClusterJ and ClusterJPA, a plugin for use with OpenJPA,
both of which became available in MySQL Cluster NDB 7.1.

ClusterJ is a high level database API that is
similar in style and concept to object-relational mapping
persistence frameworks such as Hibernate and JPA. Because ClusterJ
does not use the MySQL Server to access data in MySQL Cluster, it
can perform some operations much more quickly than can be done using
JDBC. ClusterJ supports primary key and unique key operations and
single-table queries; it does not support multi-table operations,
including joins.

ClusterJPA is an OpenJPA implementation for
MySQL Cluster that attempts to offer the best possible performance
by leveraging the strengths of both ClusterJ and JDBC. ID lookups
and other such operations are performed using ClusterJ, while more
complex queries that can benefit from the MySQL query optimizer are
sent through the MySQL Server, using JDBC.